The invention relates generally to tool change mechanisms for machine tools.
The storage of a large number of tools for use with tool change mechanisms has been a problem. When it is only necessary to provide a modest number of tools, a circular rotary magazine can be readily mounted on the machine tool for storing the tools.
In this type of magazine, a circular or annular plate carries the tool receiving sockets and the plate is rotated to move the desired tool to the tool ready station. However, when larger numbers of tools are required, chain type storage magazines have been provided and the tool receiving sockets are carried by the chain which is moved in an established path of travel to move the sockets selectively to the tool ready station. Although the chains may be directed into paths that are not circular to better accommodate the machine tool frame, they still require a lot of space so that they become cumbersome on the machine tool. In order to conserve space, such magazines have been designed to move the chain in a tortuous path but this is expensive and subject to malfunctioning so that an excessive amount of maintenance is required. The present invention provides increased tool capacity in the magazine without the disadvantages of the chain type magazine by arranging two concentric circular rows of sockets on rigid plates and utilizing a tool transfer member for moving the tools between any one of the sockets and a tool ready position.
U.S. Pat. No. 3,760,491 discloses a tool change mechanism having a tool change arm mounted on a carrier that is pivotable between a tool change position and tool loading position as is done in the present invention. However, in that previous arrangement, the tool sockets are formed in cartridges which are removable from the chain. The carrier is provided with a clamping mechanism that clamps the cartridge to it when the carrier is in the loading position. When the carrier pivots to the tool change position, it removes the cartridge from the magazine and takes it to the tool change position where the tool change arm will operate to interchange tools between the spindle and the cartridge which is then being supported by the carrier.
The present invention retains this same concept of a pivotable carrier supporting a tool change arm to provide the same efficient operation, but a ready socket is an integral part of the carrier for movement with it between the loading position and the tool change position. When the carrier and its ready socket are in the loading position, the magazine tool transfer arm will remove the previously used tool from the ready socket and place a new tool in it for subsequent transfer to the spindle. This eliminates the complex and expensive tool storage chain with removable cartridges as well as the clamping mechanism on the carrier.